/*
 * Copyright 2002-2016 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.aop.support;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

import org.aopalliance.intercept.MethodInvocation;

import org.springframework.aop.IntroductionInfo;
import org.springframework.util.ClassUtils;

/**
 * Support for implementations of {@link org.springframework.aop.IntroductionInfo}.
 *
 * <p>Allows subclasses to conveniently add all interfaces from a given object,
 * and to suppress interfaces that should not be added. Also allows for querying
 * all introduced interfaces.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 */
@SuppressWarnings("serial")
public class IntroductionInfoSupport implements IntroductionInfo, Serializable {

    protected final Set<Class<?>> publishedInterfaces = new LinkedHashSet<>();

    private transient Map<Method, Boolean> rememberedMethods = new ConcurrentHashMap<>(32);


    /**
     * Suppress the specified interface, which may have been autodetected
     * due to the delegate implementing it. Call this method to exclude
     * internal interfaces from being visible at the proxy level.
     * <p>Does nothing if the interface is not implemented by the delegate.
     *
     * @param intf the interface to suppress
     */
    public void suppressInterface(Class<?> intf) {
        this.publishedInterfaces.remove(intf);
    }

    @Override
    public Class<?>[] getInterfaces() {
        return this.publishedInterfaces.toArray(new Class<?>[this.publishedInterfaces.size()]);
    }

    /**
     * Check whether the specified interfaces is a published introduction interface.
     *
     * @param ifc the interface to check
     * @return whether the interface is part of this introduction
     */
    public boolean implementsInterface(Class<?> ifc) {
        for (Class<?> pubIfc : this.publishedInterfaces) {
            if (ifc.isInterface() && ifc.isAssignableFrom(pubIfc)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Publish all interfaces that the given delegate implements at the proxy level.
     *
     * @param delegate the delegate object
     */
    protected void implementInterfacesOnObject(Object delegate) {
        this.publishedInterfaces.addAll(ClassUtils.getAllInterfacesAsSet(delegate));
    }

    /**
     * Is this method on an introduced interface?
     *
     * @param mi the method invocation
     * @return whether the invoked method is on an introduced interface
     */
    protected final boolean isMethodOnIntroducedInterface(MethodInvocation mi) {
        Boolean rememberedResult = this.rememberedMethods.get(mi.getMethod());
        if (rememberedResult != null) {
            return rememberedResult;
        } else {
            // Work it out and cache it.
            boolean result = implementsInterface(mi.getMethod().getDeclaringClass());
            this.rememberedMethods.put(mi.getMethod(), result);
            return result;
        }
    }


    //---------------------------------------------------------------------
    // Serialization support
    //---------------------------------------------------------------------

    /**
     * This method is implemented only to restore the logger.
     * We don't make the logger static as that would mean that subclasses
     * would use this class's log category.
     */
    private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException {
        // Rely on default serialization; just initialize state after deserialization.
        ois.defaultReadObject();
        // Initialize transient fields.
        this.rememberedMethods = new ConcurrentHashMap<>(32);
    }

}
